(1) Field of the Invention
The present invention relates to an improved process for the manufacture of coverings made of synthetic materials, particularly floors coverings.
2. Description of the Prior Art
U.S. Pat. No. 4,017,658 describes a process for producing a textured or relief surface on printed sheet material comprising the following steps:
printing an ornamental pattern on the sheet material; PA1 application of a transparent plastisol in at least one discontinuous intermediate layer on the pattern thus printed; and PA1 passing the resulting assembly through a fusing oven. PA1 initial printing of an ornamental pattern on a support, PA1 application of a discontinuous plastisol, which may include an expansion or foaming agent, over the printed pattern in a thickness of at least 100.mu. by a serigraphic method, PA1 gelling of the plastisol by exposure to an elevated temperature sufficient to cause coagulation, but lower than the decomposition temperature of any expansion agent which has been included in the plastisol, PA1 cooling and smoothing by causing the product to pass between two cylinders of the type used in embossing machines, PA1 a second printing in at least two colours, PA1 fusing of the plastisol and expansion of the foaming agent, if present. PA1 PVC: 100 PA1 Mixture of plasticizers (phtalate): 30 to 80 PA1 Kicker stabilizer (barium, cadmium): 1 to 4 PA1 Epoxide plasticizers: 0 to 5 PA1 Azodicarbonamide: 1.5 to 5 PA1 Mineral charge (chalk): 0 to 40 PA1 Various pigments: 0 to 10
The reliefs obtainable by the process of U.S. Pat. No. 4,017,658 are comparatively thin and the decorative effects provided by the combination of the printed pattern and the relief are also limited.